The present invention relates to a circuit board and a method for making an electronic circuit board and, more particularly, to a method for making a multi-layer electronic circuit board having metallized apertures which may be selectively connected and/or detached or isolated from an electrical ground plane and/or from a source of an electrical ground potential.
Multi-layer circuit boards contain and/or include electrical components which selectively and operatively populate opposed top and bottom surfaces of each board (or other respective interior portions of each of the boards), thereby desirably allowing each of the electronic circuit boards to contain and/or include a relatively large amount of electrical components which efficiently and densely populate the respective boards.
It is desirable to allow for communication by and between and/or interconnection of the component containing surfaces and/or portions of an electronic circuit board, thereby allowing the contained electrical components on each side of the board (or within certain interior portions of the board) to cooperatively and selectively interconnect to form one or more desired electrical circuits. This communication and interconnection may require the use of shared electrical ground planes, the transmittal of electrical power and/or control type signals between each of the component containing surfaces and/or the component containing board portions, and/or the selective and physical connection of various contained components.
This desired interconnection typically requires that one or more holes be drilled through each of the circuit boards, thereby creating at least one xe2x80x9cthrough holexe2x80x9d or xe2x80x9cviaxe2x80x9d lying and/or traversing between some or all of the opposed component containing surf aces and through some or all of the various component containing interior circuit board portions. Such drilling is undesirable since it is relatively time consuming, costly, potentially causes damage to significant numbers of the formed electronic circuit boards requiring these circuit boards to be destroyed, and requires costly and inefficient electroless and/or electrolytic plating of the formed holes or xe2x80x9cviasxe2x80x9d.
While some attempts have been made to obviate the need for such plating, such as by the use of a conductive epoxy within each of the drilled holes, these attempts have not produced reliable electrical interconnections and these produced interconnections are not typically adapted to allow for communication of electrical power signals by and between the board surfaces and/or by and between the board surfaces and the interior component containing portions.
There is therefore a need to provide a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks and which selectively allows grounded and nonground xe2x80x9cviasxe2x80x9d to be desirably and selectively formed.
It is a first object of the present invention to provide a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electronic circuit board forming methodologies and techniques.
It is a second object of the invention to provide a method for producing a multi-layer electronic circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electronic circuit board forming methodologies and techniques and which allows for the selective, efficient, and reliable formation of metallized apertures which cooperatively allow for communication by and between some or all of the various component containing surfaces and/or portions of the formed multi-layer electronic circuit board, which cooperatively allow for the selective interconnection of these components, and which are further adapted to selectively and communicatively receive an electrical component.
It is a third object of the invention to provide a method for producing a multi-layer circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer circuit board forming methodologies and techniques and which allows for the selective formation of metallized apertures which may be selectively connected or disconnected and/or isolated from a selectively formed electrical ground plane or bus.
According to a first aspect of the present invention, a multi-layer circuit board is provided. The multi-layer circuit board comprises a first electrically conductive member having a first surface, a second surface, and further having a stepped aperture extending through the first and second surfaces; a first dielectric material which is coupled to the first surface; a second dielectric material which is coupled to the second surface; a first circuit assembly having a second electrically conductive member which is coupled to the first dielectric material, the first circuit assembly further including a third electrically conductive member and a first core member which is contained between the second and the third electrically conductive members and which includes at least one air-bridge; and a second circuit assembly having a fourth electrically conductive member which is coupled to the second dielectric material, the second circuit assembly further including a fifth electrically conductive member and a second core member which is contained between a fourth and a fifth electrically conductive members and which includes at least one air-bridge, the second circuit assembly cooperating with the first circuit assembly and with the first and second dielectric material and with the first electrically conductive member to form a multi-layer electronic circuit board.
According to a second aspect of the present invention a circuit assembly is provided. The circuit assembly is made by the process of providing a core member; etching the provided core member effective to selectively form at least one aperture within the core member, the at least one aperture having a ridged surface; providing at least one pre-circuit assembly having a second member; attaching the at least one pre-circuit assembly to the core member; and selectively etching the second member effective to extend the at least one aperture through the second member, thereby forming a circuit board assembly.
These and other objects, aspects, and advantages of the present invention will become apparent upon reading the following detailed description in combination with the accompanying drawings.